Sangsang i hyŏnsil i toenŭn 5G ch'ongbunsŏk - Ch'oe, Si-ŏk (Kukhoe Tosŏgwan, 2019)
"2019. 03.". - "Palgan tŭngnok pŏnho: 31-9720111-001387-14"–Colophon. - "Hannun e pogi [2019. 3]"–Colophon